Bernanke is saying the economy is weak but that he still expects
growth to improve in 2011:

For a sustained expansion to take hold, growth in private final
demand--notably, consumer spending and business fixed
investment--must ultimately take the lead. On the whole, in the
United States, that critical handoff appears to be under way. ...
the pace of that growth recently appears somewhat less vigorous
than we expected. ... Incoming data on the labor market have
remained disappointing. ... Overall, the incoming data suggest
that the recovery of output and employment in the United States
has slowed in recent months, to a pace somewhat weaker than most
FOMC participants projected earlier this year. ... I expect the
economy to continue to expand in the second half of this year,
albeit at a relatively modest pace.

Despite the weaker data seen recently, the preconditions for a
pickup in growth in 2011 appear to remain in place.

So it will take further disinflation or a weaker economy for the
Fed to act. Bernanke discussed the when of QE2:

Under what conditions would the FOMC make further use of
these or related policy tools? At this juncture, the
Committee has not agreed on specific criteria or triggers for
further action, but I can make two general observations.

First, the FOMC will strongly resist deviations from
price stability in the downward direction. ... It is
worthwhile to note that, if deflation risks were to increase, the
benefit-cost tradeoffs of some of our policy tools could become
significantly more favorable.

Second, regardless of the risks of deflation, the FOMC
will do all that it can to ensure continuation of the economic
recovery. Consistent with our mandate, the Federal
Reserve is committed to promoting growth in employment and
reducing resource slack more generally. Because a further
significant weakening in the economic outlook would likely be
associated with further disinflation, in the current environment
there is little or no potential conflict between the goals of
supporting growth and employment and of maintaining price
stability.

And Bernanke made his preference clear for QE2:

A first option for providing additional monetary accommodation,
if necessary, is to expand the Federal Reserve's holdings
of longer-term securities. As I noted earlier, the
evidence suggests that the Fed's earlier program of purchases was
effective in bringing down term premiums and lowering the costs
of borrowing in a number of private credit markets. I regard the
program (which was significantly expanded in March 2009) as
having made an important contribution to the economic
stabilization and recovery that began in the spring of 2009.
Likewise, the FOMC's recent decision to stabilize the Federal
Reserve's securities holdings should promote financial conditions
supportive of recovery.

I believe that additional purchases of longer-term
securities, should the FOMC choose to undertake them,
would be effective in further easing financial
conditions.

Bernanke was not as positive on changes to the "extended period"
language or reducing the interest rate on excess reserves.

Summary: I think Bernanke is paving the way for QE2, although he
probably feels he needs more evidence of a slowing economy or
further disinflation to persuade other members of the FOMC. A
warning from a large tech company is probably significant at this
point, like from MarketWatch:
Intel cuts sales forecast citing weaker consumer PC market

"Revenue is being affected by weaker than expected demand for
consumer PCs in mature markets," the company said in a statement.

Or perhaps the unemployment rate ticking up in the August
employment report next Friday might be enough. There will be
plenty of data released before the September 21 FOMC meeting (and
if the data is weaker, the meeting might be expanded to two
days). Or perhaps the FOMC will wait until November, but it does
appears Bernanke is preparing everyone for QE2.